A few hundred demonstrators representing myriad causes -- from abortion rights to economic reform -- gathered Tuesday outside Hofstra University as the nation focused on the second presidential debate.

The protests were punctuated by three arrests, including the Green Party's presidential candidate and her running mate, who objected to not being included in the debate and briefly blocked the university's main entrance.

Jennifer Kimmins, 53, of Floral Park, stood along Hempstead Turnpike holding a white sheet emblazoned with the message, "Welcome Mitt. Not all New Yorkers are liberal Democrats."

The Republican, an unemployed executive assistant, said she felt compelled to come out to show her support.

Anthony Zenkus, an Occupy Wall Street demonstrator, came to protest the two-party system. "Neither party is willing to put bankers in jail for the crimes they committed in crashing this economy," he said.

Nassau police estimated more than 300 protesters gathered at two locations.

Some groups set up outside Hagedorn Hall, about a half-mile from where other protesters gathered by the main entrance. The Hagedorn Hall groups represented Planned Parenthood and those opposing animal cruelty and war. They addressed the crowd from a small stage.

Green Party presidential candidate Jill Stein and her running mate, Cheri Honkala, were arrested about 4 p.m. for blocking the main gates and refusing to leave, Lack said.

The pair were charged with disorderly conduct.

Shortly before 8 p.m., an unidentified man was also arrested and charged with disorderly conduct in the same area, police said.